Captain Syrup made her debut appearance in Wario Land: Super Mario Land 3, where she is captain of the Brown Sugar Pirates, as her pirate gang has been originally named in English. In this game the protagonist, Wario, still reeling from his defeat at the hands of Mario and the loss of his castle, sets out to find new riches. However, instead of finding a job or traveling the world for lost treasure, Wario decides to make his fortune the old fashioned way - by stealing all the treasures he can from someone else. That someone happened to be Captain Syrup.

Wario hears of the Brown Sugar Pirates, who have stolen thousands of treasures from many different lands in the past. One of their treasures is a giant golden monument of Princess Toadstool that they are apparently holding for ransom to the Mushroom Kingdom. Wario battles members of the Brown Sugar Pirates as he ventures across the island, taking whatever treasure he can find. Ultimately, Wario decides to raid Syrup Castle, the location of Captain Syrup and her hoard of treasure.

When Wario arrives to challenge Syrup and plunder her fortunes, he is surprised to find that Syrup is a woman. Syrup summons a genie named Denpū from a magic lamp, hops onto the genie's shoulders, and the two fly around, launching fireballs at Wario. Eventually, Wario defeats the genie; however, Captain Syrup escapes by blowing up her own castle, promising to get her revenge. Wario escapes, and the giant statue is exposed. However, Mario arrives and takes the golden statue away from the greedy anti-hero. Fortunately for Wario, he still has most of his treasures, and he buys himself a new castle with Denpū's wish.

Captain Syrup strikes back in Wario Land II. In this game, her pirate gang is renamed the Black Sugar Gang in English, as the pirates have always been known in Japanese. Syrup leads her pirates in a raid on Wario Castle and steals all of his riches. As such, Wario returns to Kitchen Island to retake all the treasures that were stolen from him. Wario battles Syrup several times during this adventure, compared to just once. In battle, Captain Syrup will throw bombs at Wario, dash at him and control a robot from one of her various aircrafts. Eventually, Wario defeats Syrup in combat and takes back all of her treasures. After Syrup's final defeat to Wario in this game, she was not heard from for a lengthy period of time.

In Wario Land: Shake It!, Captain Syrup observes the crisis of the Shake Dimension inside the Ancient Globe and finds out the existence of the Bottomless Coin Sack, possessed by the evil Shake King. Desiring the treasure but not wanting to get it herself, she steals the Ancient Globe and gives it to Wario, who travels to the dimension to get the sack for himself. Captain Syrup's role in the game is to sell Wario maps of continents after he defeats a boss. At the end of the game, Wario takes the Bottomless Coin Sack for himself, but Captain Syrup takes it while he's not looking and runs off.

Captain Syrup has a new ship in this game, The Sweet Stuff. While the SS Teacup literally took the form of its namesake, this vessel is shaped to resemble a treasure chest.

In Syrup's first two appearances, she appears as a very tall and developed brunette. Syrup's hair was long, curly, and reddish-brown. Syrup wore yellow cloths throughout her outfit, all of which were tied with twin bow-like ends. One as a bandanna on her head, two tied around her wrists, and one tied around her waist as a belt. Syrup wore a cyan one-piece outfit which had large puffy leggings, was rounded at the hips, and had two loops at each shoulder. Syrup also wore semi-long dark green boots, and pink skull earrings. Syrup's eyes were brown, and she wore red lipstick. Aside from her individuality, Syrup's facial structure and features were very undefined and generic.

In her re-debut in Wario Land: Shake it!, Syrup's design is revamped. Her former cyan clothing is replaced with a new purple-based design. No longer wearing a one-piece suit, Syrup now wears a light purple top mimicking the appearance of the last outfit's design. She also wears a large red belt with a white skull buckle, and capri-length, purple, puffy pants with torn leg openings. Replacing her green boots are purple boots with light bottoms, and a pink roll-over ankle. She has light-purple wraps with long strands, and a light purple bandanna. Her accessories include a tooth-like necklace, and golden octopus earrings. Her hair is describable as red, and it is very curly with short, sharp, bangs.

In the American instruction manual of the game Wario Land: Super Mario Land 3, Captain Syrup is always referred to with gender-neutral words, although it implies that the character is male. This is possibly referencing when Wario is surprised to find Captain Syrup is a girl.

In a Nintendo Power guide, Captain Syrup was mistakenly referred to as "The Princess".

When the story of Wario Land: Shake It! was revealed in the Japanese Famitsu magazine, Captain Syrup was referred to as Maple, implying that her full name is Captain Maple Syrup.[1] However, the name Maple is never used in the game at all.